Understandable. If you ask me, I'm not very fond of the k812 since it seems to measure rather mediocre for a flagship and it doesn't quite seem to be that amazing.
Wouldn't buy pm-1 either because it seems to roll the treble and just isn't very convincing to me either.
Nor would I buy the Audeze, they are too heavy. The sound could convince me though, but I'd want to demo them first.
But is there a set of headphones you would recommend for this? I can't be the first guy planning to plug a set of high-end headphones straight into a nice DAC. Are there any that could sound better than the K812 without an amp? There is quite a "smartphone" buzz around the K812.